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View Full Version : Diamond (tangent) tool holder, which construction is better?



Elninio
02-26-2011, 07:16 PM
I've seen two types; one which has a V notch on the holder and a V notch on the clamp, and another one which has the square channel (that holds the cutting bit) directly on the edge (so its actually a three-sided channel) holding the cutter with an orthogonal screw. The former is a more rigid set-up. But, is the latter sufficient for doing heavy cuts, or interupted cuts (or was it designed just for finishing cuts)?

Lew Hartswick
02-26-2011, 07:41 PM
The former is a more rigid set-up. Why do you say that? Or is it one of those "intuitive" things?
The "square" notch can be just as "rigid" and is a lot easier to machine.
I've made both. The one I made using a triangular bit for
threading was the only one with the odd clamp config. the others
were all the square notch and a clamp bar, not just a screw head to
hold the bit. Just as rigid as a conventional bit configuration. It is
mostly a design of the holder bar.
...lew...

Elninio
02-27-2011, 12:08 AM
Why do you say that? Or is it one of those "intuitive" things?
The "square" notch can be just as "rigid" and is a lot easier to machine.
I've made both. The one I made using a triangular bit for
threading was the only one with the odd clamp config. the others
were all the square notch and a clamp bar, not just a screw head to
hold the bit. Just as rigid as a conventional bit configuration. It is
mostly a design of the holder bar.
...lew...

Because the bit is held by more surface area. Additionally, the former model has clamping four on two axes and two direction (all four sides), whereas the latter has only on two sides. The latter stays in place by the cutting force generated by the cut, pushing it into the back seat of the channel. Also, since the force isn't equally distributed in the latter (something like a point load on the screw, the bar is unsupported at the top and bottom ends), I would imagine it contributing less to the frictional force keeping it in place. This could lead to chattering (but what I'm asking, is it a negligible chatter, i.e what we practically observe as no chatter at all?).

I like that the former style lets you hold a square and round HSS bit (not sure how well the HSS holds up in heavy cuts - since you're claming a square clamp around a round bit). If I was doing it for only round bits, I would drill a channel as the proper angle, and have it clamp C-style. That would be best. For square bits, even better than both methods if you could 'drill' a square hole (one hobbyist's page I read drills undersize, and then broaches with a broach made from an HSS bit of the right size on his arborpress).

Arthur.Marks
02-27-2011, 11:08 AM
I simply don't know the answer to your question, but I have wondered it before. I've been interested in trying the diamond toolholder (Bay-Com (http://bay-com.com/product-list.php?DIAMOND_TOOLHOLDER-pg1-cid35.html)style) of late. The ironic part is that I could get a new Ifanger (http://www.ifanger.com/index.php?id=68&L=1) tangential holder + bit for the same money. I've been debating the two. The Ifanger, of course, doesn't use any ol' square tool bit. The bits on the Ifanger roughing tools are serrated (http://www.ifanger.com/fileadmin/Webmaster/katalog/pdf/01_2006_e.pdf) on the back which fit serrations on the clamping toolholder. This would seem to give the most rigidity and the most surface area.

...but then again, is it really an issue to begin with? Which leads me back to your original question ;)

mc_n_g
02-27-2011, 04:43 PM
What ever you use make usre the clamping force is along as much of the bit as possible. The 3 sided design would be ok but you only would have one surface pushing against the back of the square cut. In a clam-shell style you are bearing on the corners potentially with more nearing surface. Note I said potenitally. If your angle is larger than 90 degrees then it will most likely put pressure on one side of the bit as it is canted in the holding area. The more holding power you have the better.
I have had a BayCom toolholder for a number of years and use it along with many other tools. It has positives and negatives. Would I buy it again...maybe. It is nice but certainly not the end all tool I would olny use on my lathe. I grind a lot of HSS tools and also use carbide and HSS inserts. On certain jobs I love the BayCom toolholder but for other jobs it does not work out for me.
One bad thing with all tangential toolholders is if the corner wears down you have to grind a lot of material off the top or grind a larger radius on the cutting corner to get a new keen cutting edge.
If you can make one or get one cheap I would do it. There are many other tools you can buy or HSS blanks you can sharpen for the money. Everyone is different in their opinions.

PixMan
02-27-2011, 05:08 PM
Glad I clicked on the links provided by Arthur.Marks because I couldn't figure out if the OP was referring to single crystal diamond tooling or diamond-shaped carbide inserts or what. ;)

First time I've ever seen those type of holders for HSS tooling. The name of "diamond tooling" is very misleading for someone like me. I thought the OP was talking about holders like these:

http://img.photobucket.com/albums/v466/kenm10759/Dads%20shop/422322392_photobucket_39767_.jpg

:D

noah katz
02-27-2011, 11:24 PM
The ironic part is that I could get a new Ifanger (http://www.ifanger.com/index.php?id=68&L=1) tangential holder + bit for the same money.

Not seeing what looks like a tangential toolholder...

Paul Alciatore
02-28-2011, 12:15 AM
Well, I clicked on the links provided by Arthur Marks and I am still confused. I think there should be a new category in the annual advertising awards, smallest photos. The only one with clear photos was Ifanger. The other two had pictures that were too small to see any details at all. I even clicked on the "larger picture" link posted below some of the photos on Bay-Com and the larger pictures were exactly the same size as the original miniatures. I can only wonder what they are trying to HIDE.

As for the original question, I have not used any of these types so I can not comment.

Paul A.




Glad I clicked on the links provided by Arthur.Marks because I couldn't figure out if the OP was referring to single crystal diamond tooling or diamond-shaped carbide inserts or what. ;)

First time I've ever seen those type of holders for HSS tooling. The name of "diamond tooling" is very misleading for someone like me. I thought the OP was talking about holders like these:

http://img.photobucket.com/albums/v466/kenm10759/Dads%20shop/422322392_photobucket_39767_.jpg

:D

Elninio
02-28-2011, 12:55 AM
I simply don't know the answer to your question, but I have wondered it before. I've been interested in trying the diamond toolholder (Bay-Com (http://bay-com.com/product-list.php?DIAMOND_TOOLHOLDER-pg1-cid35.html)style) of late. The ironic part is that I could get a new Ifanger (http://www.ifanger.com/index.php?id=68&L=1) tangential holder + bit for the same money. I've been debating the two. The Ifanger, of course, doesn't use any ol' square tool bit. The bits on the Ifanger roughing tools are serrated (http://www.ifanger.com/fileadmin/Webmaster/katalog/pdf/01_2006_e.pdf) on the back which fit serrations on the clamping toolholder. This would seem to give the most rigidity and the most surface area.

...but then again, is it really an issue to begin with? Which leads me back to your original question ;)

The Ifanger collection is very impressive, and I can see why you prefered the bay-com; you have to use the special serrated bits on the Ifanger style toolholder.

I once saw 'one-way' ball bearings, a type of ratcheting mechanism that has zero backlash engagement. I wonder if these used a sort of micro-serration. And if they did, and there are HSS bits that use this same kind of micro-serration, then the tool holder would probably not have to have serrations in it at all. This is convenient for the home machinist since we could get the bits, and make the holders ourselves. I bet they would cost a lot though ...

Elninio
02-28-2011, 01:12 AM
http://img.photobucket.com/albums/v466/kenm10759/Dads%20shop/422322392_photobucket_39767_.jpg


Oh I wrote a nice long reply, but it has six images, and when I went back to correct it, my text was gone! I'll write it again later >:L

First, I think we'd all rather have the valenite tool holders in infinite supply of inserts ... okay maybe too much to ask for, so give me one pack of 10 for each of the following geometries; round, diamond, square, threading, and in geometries for steel, brass, aluminium, tool steel, copper ... okay maybe too much to ask for, i'll just have to make it happen with with a 1" square steel bar, a slitting saw from the 50's, some broken endmills, some machine screws I found on the floor in a parking lot, hehe. Tangential tool holders are just a step closer to the luxury of indexable tooling; There is only one sharpening face, which is semi-automated by the held of a grinding jig to produce the correct angles. It's much easier to change the geometry of the square HSS bit (say you're going from brass to aluminium) this way because you would have to take about a .070" grind on one face, instead of a .500" grind on the horizontal tool on two faces.

Heavy cut w/ tangential: http://www.youtube.com/watch?v=xUAPrkC7Q-Q

How did he make this slot? It must have taken a lot of patience, because he would have had to drill the end of the slot with a small drill bit, then enlarge the hole with a small square bit, then continue with his parting blade (since he cannot approach from the exterior, because of the kink in the slot).
http://www.projectsinmetal.com/wp-content/forum-image-uploads/fenichel/Kruger-3.jpg
Nice finish as the result of reduced chatter and flex in the tool:
http://www.projectsinmetal.com/wp-content/uploads/2010/12/IMG_1535-300x224.jpg

PixMan
02-28-2011, 06:57 AM
Well, I clicked on the links provided by Arthur Marks and I am still confused. I think there should be a new category in the annual advertising awards, smallest photos. The only one with clear photos was Ifanger. The other two had pictures that were too small to see any details at all. I even clicked on the "larger picture" link posted below some of the photos on Bay-Com and the larger pictures were exactly the same size as the original miniatures. I can only wonder what they are trying to HIDE....



You sure are right about that! It was only when I looked at the Ifanger product that I understood what the "diamond tangental tool" thing is all about. It's pretty good indeed, as a means to get the most from HSS tool bits. The holder appears to be a challenging one to make yourself, but doable with time and patience. I have little of either of those two.




First, I think we'd all rather have the valenite tool holders in infinite supply of inserts ... okay maybe too much to ask for, so give me one pack of 10 for each of the following geometries; round, diamond, square, threading, and in geometries for steel, brass, aluminium, tool steel, copper ...


I really don't think "we'd all like to have" those. Most home shop machines cannot possibly justify carbide insert tooling for the lack of spindle speeds and HP. In some cases, even brazed carbide is a risky investment.

FYI, those two holders did cost a about $100 each new, but the inserts (bought new in packs of 10) were more than twice that. Fortunately for me, I know how to shop Ebay and those holders (together) were under $50 (shipped) and I got a lot of inserts from a friend, but many from the sales that JT Machinery & Supply of Mentor OH has on a weekly basis. The latest was a 14-page list of a wide variety of inserts at $1.95 each. Many thousands available, mix & match two of these, 3 of those, etc. So I did.

You can get one grade to machine steels and most stainless steels, and one for all aluninum, brass and other non-ferrous, plastic and non-metal materials. You may wish to add later, differing grades and chipbreakers as the need or desire to do so arises. If one really insists upon carbide insert tooling, I can help select something that might work and do so within budget.

I am VERY impressed with the holder shown. The slot with a kink in it is a work of art, from a technical standpoint. Is that yours, Elninio? If I was making one, I think I would've have been fine with the one angled slot. That long, kinked slot seems nice, but perhaps overkill. In what appears to be soft steel I don't believe you don't gain any additional clamping, but may some lose rigidity.

If one is to make their own "diamond tangental" tool holder, is there a guide or prints for making one? Also, are there drawings for the mating grinding fixture? Looks like it would be an interesting project. I know it can be hard (and expensive) to get the Ifanger products here in the US. I believe Alloutette Tool of NY is still the sole importer.

Elninio
02-28-2011, 08:22 AM
I'm working on a design now, mainly thinking of a way to produce the square notch. If I had really small tools, I would do it this way: drill your hole, then cut with a slitting saw the cutting edges (axial and diametral). Then cut the angular slit which bisects the cutting edge with much thicker saw. You'll have the frontal edges of the channel flat, the back two with a minor radius on them. Maybe the HSS bit will dig into the radiused edge over time - its a good thing but don't count on it.

The design is simple once you figure out the angles, there are four of them; axial and diametral relief, axial and diametral rake. I think they occasional are called 'end' or 'frontal', but this is confusing. Intuitively you might decide to combine the angles (because while you're thinking of it, you're also thinking of your grinding bit, i.e possibly you want to sharpen the HSS bit while in the holder, since it has flat edges). This won't work and I'm sure you all know this, as by the definition and purpose of relief and rake.

I then found a table on recommendations for angles per material. I think this could use improvement since we are not discussing the material of the cutting bit (HSS, HSS with cobalt 5%, 10%, carbide, self-hardened bits and other wacky creations [maybe you're cutting a lot of plastics?]). Since we're working as a community on this, I think we can afford to discuss the angles to this level of perfection, but the following chart is a for the average small lathe (and note it doesn't discuss plastics). The angles are in order of [diametral(side) relief, axial (end) relief, diametral rake, axial rake.

Alum: 12, 8, 16, 35
Brass/Bronze: 10, 8, 5 to -4, 0
Cast Iron: 10, 8, 12, 5
Copper: 12, 10, 20, 16
Steel: 12, 8, 12 to 18, 8 to 10
Tool Steel: 10, 8, 12, 8
Stainless Steel: 10, 8, 15 to 20, 8

For some materials, rake has a range of values, I don't know if this is due to preference or to different grades of brass/bronze. So your holder with have the relief values, and your HSS bit will be ground to the rake angles.

The combinatronics produces many tool holders which need to be machined, so I've prioritized four for the average machinist;

(1)Cutter for Alum and steel; 12deg axial relief, 8deg diametral relief.
(2)Cutter for Brass/Bronze Tool Steel, Stainless Steel; 10deg axial relief, 8 deg diametral relief.
(3)Cutter for Copper; 12deg axial relief, 10deg diametral relief.

You'll notice that the 12deg axial relief and 8deg diametral relief is common amongst two of the holders, so pick option (1) to machine first, and if you're unsatisfied with its performance choose (2) and (3) next. I'd also like to have a holder to use 3/8ths shank broken endmills, so I'll be machining this one first, since it's the easiest (since you're drill a hole, not shaping one or broaching one). I'll machine this one first to the specs of (1).

For plastics, most likely you won't need to make a tangential tool holder. I'm saying maybe because the holder offers more than just a rigidity bonus. The holder will also reach into nooks and crannies better than putting a bit directly in your four-way toolpost. Also there's the single-face sharpening bonus; I don't know how often HSS bits dull on plastics (probably never). Maybe you have a special plastic that has abrasives in it, or you're machining graphite ...

@Pixman; its not mine, I found it using google images, and the link is to some forum that i'm not a part of. I didn't feel like registering but now you've sparked my curiosity ...

John Stevenson
02-28-2011, 08:39 AM
How did he make this slot? It must have taken a lot of patience, because he would have had to drill the end of the slot with a small drill bit, then enlarge the hole with a small square bit, then continue with his parting blade (since he cannot approach from the exterior, because of the kink in the slot).
http://www.projectsinmetal.com/wp-content/forum-image-uploads/fenichel/Kruger-3.jpg


Two pieces, you can see the join line at the end of the slot.

PixMan
02-28-2011, 09:09 AM
Two pieces, you can see the join line at the end of the slot.

Good eye John. That also makes it a LOT easier to make, for sure. The "pocket" for the tool bit is easier to create too, not needing a square broach or shaper to make it.

dian
02-28-2011, 09:10 AM
my ifanger tools:

http://i973.photobucket.com/albums/ae218/romandian/mkbohrer009.jpg

on the roughing and finishing holders only the clamps are serrated.

Arthur.Marks
02-28-2011, 09:22 AM
Here is a simple visual aid to the discussion. Yes, as mentioned, Bay-Com provide horrible, tiny images of the product. They are distributors for Eccentric Engineering in Australia who actually make the holder. Their images are far, far, far more informative: http://www.eccentricengineering.com.au/index.php?option=com_content&view=article&id=2&Itemid=18

Arthur.Marks
02-28-2011, 09:28 AM
I might also add that the book "The Modern Watchmakers Lathe And How To Use It" by A. Perkins explains a toolholder which is for all purposes the same as the tangential, "diamond" toolholders we are discussing here. In that book, I was curious to note, it is listed as a profiling tool and uses round HSS blanks to produce different radiuses. See pg. 253, Fig. 10

lazlo
02-28-2011, 04:32 PM
Heavy cut w/ tangential: http://www.youtube.com/watch?v=xUAPrkC7Q-Q

"A New Approach to Metal Turning." LOL! :D

Someone should send him a copy of Robert Smith's "Advanced Machine Work" from 1912, which has great pictures/description of the diamond tool, complete with sharpening directions.

Rich Carlstedt
02-28-2011, 08:13 PM
Not only was the Diamond tool in American Machinist Back around 1900,
it was on their front page. I have a copy somewhere

Rich

Elninio
03-01-2011, 11:27 AM
Not only was the Diamond tool in American Machinist Back around 1900,
it was on their front page. I have a copy somewhere

Rich

I thought so too, but why did it never go mainstream?

Black Forest
03-01-2011, 12:02 PM
A while back I sent and email asking if it was available in Germany. They never responded and I never pursued it after that. I would like to buy one but I don't know where to get one here.

dian
03-01-2011, 02:16 PM
for two horseshoes (made on your big saw) i will send you an ifanger tool.